For example, U.S. Pat. No. 4,347,846 has already disclosed a surgical extractor of this kind comprising:                a flexible tube which is able to penetrate inside said passages as far as a body to be extracted;        a longitudinally rigid maneuvering wire which is able to slide in said flexible tube and can be maneuvered slidably, from the outside, via its proximal end; and        a plurality of extraction wires arranged at the distal end of said maneuvering wire and capable of adopting, under the action of the latter:                    either a trapping position, for which they are arched and spaced apart from one another, forming, outside the distal end of said flexible tube, an openwork cage in the at least approximate shape of a globe, each arched wire forming a meridian thereof,            or an extracting position, for which they are situated near to one another and retracted at least partially inside the distal part of said flexible tube.                        
In a known extractor of this kind, all of said extraction wires are made integral with one another at their distal ends by welding or similar, forming a tail protruding at the distal end of said cage.
This protruding tail has the disadvantage of preventing the distal end of the extractor from closely approaching the wall of the organ containing said foreign bodies for the purpose of trapping those situated in proximity to said wall.
Thus, in order to overcome this disadvantage, it has already been proposed (see, for example, WO 99/16364 and WO 99/53849) to omit said protruding tail by forming in one piece each pair of meridian wires situated in the same meridian plane of said cage. Thus, the latter is then formed by a plurality of independent meridian loops intersecting at the distal end of said cage.
Although such a solution indeed makes it possible to omit the distal tail mentioned above, and thus to take hold of foreign bodies near the wall of the organ containing them, it by contrast has the disadvantage that the independent meridian loops are free in relation to one another so that their relative positions and their squareness to one another can vary considerably, which leads to difficulties in grasping and/or extracting said foreign bodies.
To overcome this new disadvantage, it has therefore been proposed (see, for example, U.S. Pat. No. 5,057,114, U.S. Pat. No. 5,484,384 and U.S. Pat. No. 5,989,266) to integrate said meridian loops to one another at their distal ends, at the place where they intersect. However, doing so gives said cage a certain rigidity, preventing it from adapting to a foreign body to be extracted and to the environment in which it is situated.